Conventionally, a liquid crystal display device including a flexible substrate as a substrate included in a liquid crystal cell is known. An example of flexible substrate is a substrate formed of a resin (resin substrate). Such a liquid crystal display device may be entirely curved or folded, and may be treated as paper. For such a property, a liquid crystal display device including a flexible substrate (namely, a flexible liquid crystal display device) is also called a “sheet display”.
A flexible substrate included in a liquid crystal display device is much thinner than a glass substrate. Therefore, a highly rigid substrate needs to be used in order to support the flexible substrate in a production process of the liquid crystal display device. A liquid crystal display device including a flexible substrate is produced as follows, for example. A resin layer is formed on a glass substrate, and a semiconductor device and the like are formed on the resin layer. Then, after a liquid crystal cell is completed, the glass substrate and the resin layer are peeled off from each other. Thus, the resin layer acts as a flexible substrate of the liquid crystal display device. Japanese Laid-Open Patent Publication No. 2013-235196 describes a flexible liquid crystal display device produced in such a production process.